There are two growing technologies that complement each other yet generate a need to solve issues regarding the combination of the two. 1) High definition (HD) video is the next generation of video which includes much more data than standard definition video thus enabling much clearer and more vivid video. Since HD video includes so much data, to transport the data from one location to another, particularly, wirelessly, utilizes a significant amount of bandwidth. To decrease the utilized bandwidth while preserving the HD quality, encoding/compression schemes are utilized when transmitting the data. 2) Real-time transmission of data enables real-time and interactive applications such as video conferencing and online gaming. In real-time video transmission, it is important to adapt the data rate with respect to the changes of the available bandwidth, which requires scalable encoding/compression schemes performed to the video data.
One example of wireless transmission is Wireless HD 1.0. The Wireless HD 1.0 standard defines a wireless video area network (WVAN) for the connection of consumer electronic (CE) audio and video devices. A key attribute of the WirelessHD system is its ability to support the wireless transport of an uncompressed 1080 p A/V stream with a high quality of service (QoS) within a room at distances of ten meters.
The requirement for high data throughput at distances of 10 meters requires a large allocated frequency spectrum. A large amount spectrum is available on an unlicensed basis in many countries in the 60 GHz band. In North America and Japan, a total of 7 GHz is allocated for use, 5 GHz of which is overlapping. The band 57˜64 GHz is allocated in North America while 59-66 GHz is allocated in Japan. In addition, Korea and the European Union have also allowed similar allocations. The regulator agencies allow very high effective transmit power (the combination of transmitter power and antenna gain), greater than 10 W of effective isotropic radiated power (EIRP). High EIRP and wide allocated bandwidth will allow high throughput connections that, however, are very directional.
The WirelessHD 1.0 specification defines a wireless protocol that enables directional connections that adapt very rapidly to changes in the environment. This is accomplished by dynamically steering the antenna beam at the transmitter while at the same time focusing the receiver antenna in the direction of the incoming power from the transmitter. This dynamic beam forming and beam steering utilizes not only the direct path, but allows the use of reflections and other indirect paths when the line-of-sight connection is obstructed. This dynamic adjustment of the antenna energy is completed in less than one millisecond.
The WVAN includes one Coordinator and zero or more Stations. The Coordinator schedules time in the channel to ensure that the wireless resources are prioritized for the support of A/V streams. The other devices that are a part of the WVAN are referred to as Stations. A station may be the source and/or sink of data in the network. The device that is the Coordinator also acts as a Station in the WVAN and may act as a source and/or sink of data. <http://www.wirelesshd.org/technology.html>